The electrical energy requirement of elevators varies at different times. During a run the power requirement is essentially greater than during a standstill of the elevator. The load of the elevator car as well as, inter alia, the magnitude of the counterweight of the elevator car affect the power consumption during a run.
The fuses of a rising main in a building as well as the cables are usually dimensioned according to a greater required power. Generally the costs of a mains electricity connection of a building increase when the dimensioning of the fuses/the power requirement of the building increases.
From the viewpoint of the electricity provider, a wide-ranging power variation can be a problem, because it might cause, among other things, oscillation in the frequency of the electricity network.